4AB › Chemistry PYQ › CSIR-NET › June 2018 › Q49Q49 · CSIR-NET Chemistry, June 2018 Paper: CSIR-NET June 2018 · Subject: Inorganic Chemistry · Chapter: Organometallic Compounds · Topic: Cluster Compounds Wade Rules · Marks: 2 · Difficulty: Medium
Which of the following are NOT closo clusters? \[ \left[\left\{\mathrm{Co}(\eta^{5}\text{-}\mathrm{C}_5\mathrm{H}_5)\right\}_{2}(\mathrm{C}_2\mathrm{B}_6\mathrm{H}_8)\right]\text{(A)}\;\left[\mathrm{B}_4\mathrm{C}_2\mathrm{H}_8\right]\text{(B)}\;\left[\mathrm{B}_{10}\mathrm{H}_{13}\{\mathrm{Au}(\mathrm{PPh}_3)\}\right]\text{(C)}\;\left[\mathrm{C}_2\mathrm{B}_8\mathrm{H}_{10}\right]\text{(D)} \]
(a) (C) and (D)
(b) (A) and (B)
(c) (A) and (C)
(d) (B) and (C)
Answer Answer: D ✓ checked by 4AB · confidence high
Explanation Skeletal pairs: A [(CpCo)₂C₂B₆H₈] 10 vertices, 2×2 + 2×3 + 6×2 = 22 e = n + 1 pairs → closo; B [B₄C₂H₈] 6 vertices, 8 + 6 + 2 extra H = 16 e → nido; C [B₁₀H₁₃(AuPPh₃)] is nido-B₁₀H₁₄ with Au(PPh₃) in place of H; D C₂B₈H₁₀ 10 vertices, 22 e → closo. Not closo: B and C.
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